In recent years, much attention has been paid to contactless power transmission (wireless power transfer) in which electromagnetic induction is used to make power transmission possible without a metal contact. Charging of electronic apparatuses such as a household appliance and a mobile terminal has been proposed as an application example of the contactless power transmission.
Known technologies of the contactless power transmission include technologies disclosed in Patent Documents 1 to 4, for example. In these known technologies, data is communicated from a power receiving side (secondary side) to a power transmitting side (primary side) using load modulation, and various types of information on the power receiving side is transmitted to the power transmitting side.